Compared with the invasive population, the seed germination of the local population of Solidago canadensis is more sensitive to soil microplastics

Experimental sources: The experimental subjects were Canadian goldenrod seeds from North America (SNA-A), Canadian goldenrod seeds from North America subjected to warming treatment (SNA-W), Canadian goldenrod seeds from China (SCN-A), and Canadian goldenrod seeds from China subjected to warming treatment (SCN-W). Microplastic concentration: Five mass fraction gradients were set at 0%, 1%, 2%, 4%, and 6%. Experimental period: From April 2025 to May 2025. The seed germination indicators mainly measured the initial germination time, germination potential, germination rate, and seedling length of Canadian goldenrod seeds, and calculated the germination index and vigor index. Initial germination period: The time of the first germination after sowing. Germination potential: Calculated based on the number of germinated seeds on the 7th day after sowing. Germination rate: Calculated based on the number of germinated seeds on the 15th day after sowing. Seedling length: On the 15th day, five germinated seeds with moderate growth were selected, and their lengths were measured using a vernier caliper (mm). Thousand-seed weight: In this experiment, the thousand-seed weight was determined by the hundred-seed weight method. One hundred seeds were randomly selected and weighed using a precision electronic balance with an accuracy of 0.0001g, and this process was repeated five times.